Displaying publications 1 - 20 of 106 in total

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  1. Ab Rahman MF, Rusli A, Misman MA, Rashid AA
    ACS Omega, 2020 Nov 24;5(46):30329-30335.
    PMID: 33251468 DOI: 10.1021/acsomega.0c04964
    With increased awareness on the importance of gloves arising from the COVID-19 pandemic, people are expected to continue using them even after the pandemic recedes. This scenario in a way increased the rubber solid waste disposal problem; therefore, the production of biodegradable gloves may be an option to overcome this problem. However, the need to study the shelf life of biodegradable gloves is crucial before commercialization. There are well-established models to address the failure properties of gloves as stated in the American Society for Testing and Material (ASTM) D7160. In this study, polysaccharide-based material-filled natural rubber latex (PFNRL) gloves, which are biodegradable gloves, were subjected to an accelerated aging process at different temperatures of 50-80 °C for 1-120 days. Prediction models based on Arrhenius and shift factors were used to estimate the shelf life of the PFNRL gloves. Based on the results obtained, the estimated time for the PFNRL gloves to retain 75% of their tensile strength at shelf temperature (30 °C) based on Arrhenius and shift factor models was 2.8 years. Verification on the activation energy based on the shift factor model indicated that the shelf life of PFNRL gloves is 2.9 years, which is only a 3.6% difference. The value obtained is aligned with the requirement in accordance with ASTM D7160, which states that only up to a maximum of 3 years' shelf life is allowed for the gloves under accelerated aging conditions.
    Matched MeSH terms: Latex
  2. Raju G, Mas Haris MRH, Azura AR, Ahmed Mohamed Eid AM
    ACS Omega, 2020 Nov 10;5(44):28760-28766.
    PMID: 33195929 DOI: 10.1021/acsomega.0c04081
    The slow-release mechanism of copper into soil followed by soil biodegradation was studied using the chitosan (CTS)/epoxidized natural rubber (ENR) biocomposite. The biocomposite was prepared by homogenizing CTS in ENR50 (ENR with about 50% epoxy content) latex in the presence of curing agents and acetic acid. It was found that the adsorption property of the biocomposite was very much influenced by chitosan loading, where 20phrCTS-t-ENR biocomposite can absorb 76.31% of Cu(II) ions. The desorption study indicates that the copper (II) ion can be released at a very slow and control phase as proven by the kinetic study using zero-order, first-order, Higuchi, and Korsmeyer Peppas equations. The slow-release studies comply with the Higuchi square-root equation, indicating that the release process is diffusion-controlled. Results of desorption and biodegradation process suggest that this biocomposite has the potential use of being a slow-release matrix in the field of agriculture.
    Matched MeSH terms: Latex
  3. Das S
    ANZ J Surg, 2008 Nov;78(11):939.
    PMID: 18959687 DOI: 10.1111/j.1445-2197.2008.04708.x
    Matched MeSH terms: Latex/adverse effects*; Latex Hypersensitivity/epidemiology*
  4. Devaraj, V., Zairossani, M.N.
    ASM Science Journal, 2012;6(1):15-21.
    MyJurnal
    Malaysia is the world’s top manufacturer of examination and surgical natural rubber (NR) gloves, exported mainly to the USA and Europe. The glove manufacturing process yields effluent which must be treated to comply with the stringent regulatory requirements imposed by the Malaysian Department of Environment. To make glove manufacturing an eco-friendly process, efforts are geared towards minimizing and utilizing waste or converting it into raw material for making value-added products. Waste generated from the glove industry is mainly rubber sludge which is obtained from the chemical flocculation stage of the effluent treatment process and consists of mainly rubber, remnants of compounding ingredients and water. R&D work by the Malaysian Rubber Board on waste utilization and resource recovery investigations have revealed many uses for this sludge. This paper briefly outlines only one of the many options available, which is the conversion of the sludge into sludge derived fuel (SDF). Preliminary study has identified three formulations of SDF with calorific values (CV) exceeding 16 000 kJ/kg, matching a good grade coal. This was considered as promising results which warrant explorative work for further increasing the CV of SDF to turn it into a viable fuel substitute in the latex products manufacturing industry and subsequently apply for a Clean Development Mechanism status to generate income.
    Matched MeSH terms: Latex
  5. Naji, H.R., Sahri, M.H., Bakar, E.S., Soltani, M., Hamid, H.A.
    ASM Science Journal, 2014;8(1):36-43.
    MyJurnal
    Wood density and types of shrinkage were examined in two rubberwood latex timber clones of rubber (Hevea brasiliensis) namely RRIM 2020 and RRIM 2025, planted at densities of 500, 1000, 1500, and 2000 trees/ha, within a trial plot. The mean wood density showed a low descending trend towards high planting densities in both clones. Wood density was significantly and negatively correlated with planting density. The strength of correlation was moderate. The mean longitudinal shrinkage in both clones and tangential shrinkages in clone RRIM 2020 showed no significant difference among planting densities. The tangential (in RRIM 2025), radial and volumetric shrinkages in both clones decreased from low to high planting densities and the differences were more pronounced between densities of 500 trees/ha and 2000 trees/ha. The magnitudes of correlation between these shrinkages and planting density were low. The regression models indicated that wood density could be more ascribed by planting density followed by volumetric shrinkage. This study exhibited low variations in wood density and shrinkages among clones and the respective planting densities; however, RRIM 2025 was more stable than RRIM 2020.
    Matched MeSH terms: Latex
  6. Sofian Ibrahim, Keong, Chai Chee, Ratnam, Chantara Thevy, Khairiah Badri
    ASM Science Journal, 2018;11(2):67-75.
    MyJurnal
    Radiation pre-vulcanised natural rubber latex (RVNRL) prepared by using gamma irradiation technique has many advantages over the conventionally prepared sulphur pre-vulcanised natural rubber latex (SPVL). Despite the fact that many potential latex dipped products can be made from RVNRL, little effort was made to fully commercialise the products because of the inferior strength of RVNRL products compared to SPVL products. An attempt was made to improve the tensile strength of RVNRL by combining both radiation and peroxide vulcanisation in order to ensure that the products will not tear or fail, and has sufficient stretch. Hexanediol diacrylate (HDDA) plays the main role as sensitizer during radiation vulcanisation and tert-butyl hydroperoxide (t-BHPO) as the co-sensitizer in peroxide vulcanisation. Pre-vulcanised natural rubber latex dipped films via hybrid radiation and peroxidation vulcanisations obtained showed tensile strength of 26.7 MPa, an increment of more than 15% compared to controlled film (22.5 MPa). Besides, the crosslink percentage of the rubber films also showed around 5% increment from 90.7% to 95.6%.
    Matched MeSH terms: Latex
  7. Yeang HY, Ward MA, Zamri AS, Dennis MS, Light DR
    Allergy, 1998 May;53(5):513-9.
    PMID: 9636811
    Separate studies have reported spina bifida patients to be especially allergic to proteins of 27 and 23 kDa found in the serum of centrifuged natural rubber latex. An insoluble latex protein located on the surface of small rubber particles, Hev b 3, has similarly been found to be allergenic to spina bifida patients. In this study, internal amino acid sequences of Hev b 3 showed similarity to the published sequences for the 27- and 23-kDa latex proteins. The latter allergens are hence identified as Hev b 3. Determination of the molecular weight of Hev b 3 revealed various species of 22-23 kDa. The consistent gaps of about 266 Da observed between various forms of the intact protein suggest that the protein undergoes post-translational modification. To determine whether Hev b 3 also occurs in a soluble form in the latex serum, its presence in molecular-filtered serum was checked by ELISA and Western blot. The results showed Hev b 3 to be largely absent in the C-serum from fresh latex. The protein is therefore insoluble in its native state. However, a small amount of the solubilized protein was detected in ammonia-stabilized latex (commonly used in the manufacture of latex products).
    Matched MeSH terms: Latex/immunology*
  8. Turjanmaa K, Palosuo T, Alenius H, Leynadier F, Autegarden JE, André C, et al.
    Allergy, 1997 Jan;52(1):41-50.
    PMID: 9062628
    For the diagnosis of IgE-mediated (immediate) hypersensitivity to natural rubber latex (NRL), skin prick testing with extracts of latex gloves has been widely used, but such extracts are difficult to standardize. The present study aimed to produce on an industrial scale an NRL extract from freshly collected NRL and to evaluate, calibrate, and standardize the extract by both in vivo and in vitro testing. The source material, latex of the rubber tree, Hevea brasiliensis (clone RRIM 600), was frozen immediately after collection in Malaysia and shipped in dry ice to Stallergènes SA, France. Protein and allergen profiles were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), immunoblotting, isoelectric focusing (IEF), crossed immunoelectrophoresis (CIE), and crossed radioimmunoelectrophoresis (CRIE). Allergen quantification was effected by RAST inhibition. The capacity of the preparation to elicit immediate hypersensitivity reactions in vivo was measured by skin prick testing in 46 latex-allergic patients and 76 nonallergic control subjects. SDS-PAGE and immunoblot profiles of the extract and an NRL standard (E8) provided by the US Food and Drug Administration were almost identical, disclosing several distinct IgE-binding proteins with apparent molecular weights of 14, 20, 27, 30, and 45 kDa, conforming to reported molecular weights of several significant NRL allergens. An arbitrary index of reactivity (IR) of 100 was assigned to the extract at 1:200 dilution (w/v), having a protein content of 22 micrograms/ml. Skin prick testing of latex-allergic patients and controls using the extract at 100 IR revealed 93% sensitivity, 100% specificity, 100% negative predictive value, and 96% positive predictive value. In conclusion, a skin prick test reagent for diagnosis of type I NRL allergy was successfully standardized. The reagent was demonstrated to contain most, if not all, of the currently known clinically significant NRL allergens, and it showed high sensitivity and specificity.
    Matched MeSH terms: Latex/administration & dosage; Latex/immunology*; Latex/standards*
  9. Yeang HY, Yusof F, Abdullah L
    Anal Biochem, 1995 Mar 20;226(1):35-43.
    PMID: 7785777
    Many proteins derived from the latex of Hevea brasiliensis that remain soluble in trichloroacetic acid (TCA) can be precipitated by phosphotungstic acid (PTA). A combination of 5% TCA and 0.2% PTA precipitates a wide range of proteins effectively even when they are present in low concentrations (below 1 microgram ml-1). In addition to its protein purification function, acid precipitation also increases the sensitivity of the subsequent protein assay by allowing the test sample to be concentrated. Another advantage of protein precipitation by TCA and PTA is that very small amounts of protein (of the order of 10 micrograms) can be repeatably recovered without the use of precipitate-bulking agents such as sodium deoxycholate. This general procedure of protein purification and concentration is simple and rapid, but the use of PTA may not be fully compatible with the Bradford protein assay. A modified Lowry microassay is described which enables about 3 micrograms ml-1 to be quantitated at the photometric absorbance of 0.05. When used in conjunction with protein concentration by precipitating with TCA/PTA, approximately 0.4 microgram ml-1 protein present in 6 ml of solution can be assayed.
    Matched MeSH terms: Latex/chemistry*
  10. Yeang HY
    Ann. Allergy Asthma Immunol., 2000 Jun;84(6):628-32.
    PMID: 10875493 DOI: 10.1016/S1081-1206(10)62415-5
    BACKGROUND:
    The prevalence of latex-specific IgE computed from the results of serologic assays is commonly thought to reflect, to a greater or lesser extent, the prevalence of latex allergy and its implied risk.

    OBJECTIVE:
    The study examines how imperfect test specificity of in vitro assays influences the precision of latex allergy prevalence that it estimates.

    METHODS:
    Various models encompassing a range of hypothetical test sensitivity and specificity values are investigated to gauge their influence on the estimate of latex allergy prevalence. The models examine these interactions in situations of high or low allergy prevalence.

    RESULTS:
    Serologic latex diagnostic assays with test specificity within the range of those of commercially available assays can greatly overestimate prevalence where the true prevalence is low (eg, of the order of one in 100 or one in 1,000). A formula to correct for errors in prevalence estimates arising from imperfect test sensitivity and specificity of an in vitro assay is presented.

    CONCLUSION:
    While serologic assays for latex IgE pose few hazards to the patient and are useful for confirming the diagnosis of latex allergy, the test results may vastly overestimate the true prevalence of latex allergy and its associated risks in situations where latex allergy is actually rare.
    Matched MeSH terms: Latex Hypersensitivity/diagnosis; Latex Hypersensitivity/epidemiology*
  11. Toh BH, Sengupta S, Ang AH, White JC, Lau KS
    Ann Rheum Dis, 1973 Mar;32(2):151-6.
    PMID: 4120913 DOI: 10.1136/ard.32.2.151
    In West Malaysia RA appears to be less common than in temperate climates, but more common than in tropical Africa; furthermore, the incidence of gout and SLE is comparable. The clinical manifestations of RA are milder than those seen in more temperate climates. Subcutaneous rheumatoid nodules have not been observed. Positive serological tests for RF are significantly higher than in the general Malaysian population, but still lower than those reported for patients with RA in temperate climates. Of the three main ethnic groups, the highest incidence of positive results is found in the Chinese.
    Study site: Arthritis Clinic, University Hospital, Kuala Lumpur (University Malaya Medical Centre, UMMC, Kuala Lumpur, Malaysia)
    Matched MeSH terms: Latex Fixation Tests
  12. Tang SN, Fakhru'l-Razi A, Hassan MA, Karim MI
    PMID: 10595441
    Rubber latex effluent is a polluting source that has a high biochemical oxygen demand (BOD). It is estimated that about 100 million liters of effluent are discharged daily from rubber processing factories. Utilization of this effluent such as the use of a coupled system not only can reduce the cost of treatment but also yield a fermentation feedstock for the production of bioplastic. This study initially was carried out to increase the production of organic acids by anaerobic treatment of rubber latex effluent. It was found that through anaerobic treatment the concentration of organic acids did not increase. Consequently, separation of organic acids from rubber latex effluent by anion exchange resin was examined as a preliminary study of recovering acetic and propionic acids. However, the suspended solids (SS) content in the raw effluent was rather high which partially blocked the ion-exchange columns. Lime was used to remove the SS in the rubber latex effluent. After the lime precipitation process, organic acids were found to adsorb strongly onto the anion exchange resin. Less adsorption of organic acids onto the resin was observed before the lime precipitation. This was probably due to more sites being occupied by colloidal particles on the resin thus inhibiting the adsorption of organic acids. The initial concentration of organic acids in the raw effluent was 3.9 g/L. After ion exchange, the concentration of the organic acids increased to 27 g/L, which could be utilized for production of polyhydroxyalkanoates (PHA). For PHA accumulation stage, concentrated rubber latex effluent obtained from ion exchange resins and synthetic acetic acid were used as the carbon source. Quantitative analyses from fed batch culture via HPLC showed that the accumulation of PHA in Alcaligenes eutrophus was maximum with a concentration of 1.182 g/L when cultivated on synthetic acetic acid, corresponding to a yield of 87% based on its cell dry weight. The dry cell weight increased from 0.71 to 1.67 g/L. On the other hand, using concentrated rubber latex effluent containing acetic and propionic acids resulted in reduced PHA content by dry weight (14%) but the dry cell weight increased from 0.49 to 1.30 g/L. The results clearly indicated that the cells grow well in rubber latex effluent but no PHA was accumulated. This could be due to the high concentration of propionic acid in culture broth or other factors such as heavy metals. Thus further work is required before rubber latex effluent can be utilized as a substrate for PHA production industrially.
    Matched MeSH terms: Latex/metabolism*
  13. Rahman AY, Usharraj AO, Misra BB, Thottathil GP, Jayasekaran K, Feng Y, et al.
    BMC Genomics, 2013;14:75.
    PMID: 23375136 DOI: 10.1186/1471-2164-14-75
    Hevea brasiliensis, a member of the Euphorbiaceae family, is the major commercial source of natural rubber (NR). NR is a latex polymer with high elasticity, flexibility, and resilience that has played a critical role in the world economy since 1876.
    Matched MeSH terms: Latex/metabolism
  14. Habib MAH, Gan CY, Abdul Latiff A, Ismail MN
    Biochem. Cell Biol., 2018 12;96(6):818-824.
    PMID: 30058361 DOI: 10.1139/bcb-2018-0020
    The natural rubber latex extracted from the bark of Hevea brasiliensis plays various important roles in modern society. Post-translational modifications (PTMs) of the latex proteins are important for the stability and functionality of the proteins. In this study, latex proteins were acquired from the C-serum, lutoids, and rubber particle layers of latex without using prior enrichment steps; they were fragmented using collision-induced dissociation (CID), higher-energy collisional dissociation (HCD), and electron-transfer dissociation (ETD) activation methods. PEAKS 7 were used to search for unspecified PTMs, followed by analysis through PTM prediction tools to crosscheck both results. There were 73 peptides in 47 proteins from H. brasiliensis protein sequences derived from UniProtKB were identified and predicted to be post-translationally modified. The peptides with PTMs identified include phosphorylation, lysine acetylation, N-terminal acetylation, hydroxylation, and ubiquitination. Most of the PTMs discovered have yet to be reported in UniProt, which would provide great assistance in the research of the functional properties of H. brasiliensis latex proteins, as well as being useful biomarkers. The data are available via the MassIVE repository with identifier MSV000082419.
    Matched MeSH terms: Latex/metabolism*; Latex/chemistry
  15. Habib MA, Yuen GC, Othman F, Zainudin NN, Latiff AA, Ismail MN
    Biochem. Cell Biol., 2017 04;95(2):232-242.
    PMID: 28177774 DOI: 10.1139/bcb-2016-0144
    The natural rubber latex extracted from the bark of Hevea brasiliensis plays various important roles in today's modern society. Following ultracentrifugation, the latex can be separated into 3 layers: C-serum, lutoids, and rubber particles. Previous studies have shown that a large number of proteins are present in these 3 layers. However, a complete proteome for this important plant is still unavailable. Protein sequences have been recently translated from the completed draft genome database of H. brasiliensis, leading to the creation of annotated protein databases of the following H. brasiliensis biosynthetic pathways: photosynthesis, latex allergens, rubberwood formation, latex biosynthesis, and disease resistance. This research was conducted to identify the proteins contained within the latex by way of de novo sequencing from mass spectral data obtained from the 3 layers of the latex. Peptides from these proteins were fragmented using collision-induced dissociation, higher-energy collisional dissociation, and electron-transfer dissociation activation methods. A large percentage of proteins from the biosynthetic pathways (63% to 100%) were successfully identified. In addition, a total of 1839 unique proteins were identified from the whole translated draft genome database (AnnHBM).
    Matched MeSH terms: Latex/chemistry*
  16. Nuriah Mohamad, Azlin Suhaida Azmi, Fathilah Ali, Mohamad Firdaus Omar
    MyJurnal
    Sulfur has been highly sought by many industries everywhere around the world for various applications. This exceptionally useful element has been largely manufactured especially in powder form each year reflecting its increase in demand in line with technological advancement and uses for various product applications. The manufacturing processes include mining as well as chemical reactions in Claus Process. Rubber industries normally use abundance of sulfur in their latex compound to introduce vulcanization. The geneal concern of sulfur for rubber vulcanization is dispersibility in the rubber matrix due to improper optimization of its preparation process prior to latex compounding. Another crucial issue is crystallization of soluble sulfur from its insoluble origin, either during or post-rubber vulcanization that constitutes to formation of sulfur bloom that grows on the surface of the rubber articles. It is known that both issues are related to the process conditions and compounding recipe that could not be fully solved. Various studies have been conducted to minimize such occurences – from process optimization to sulfur chemistry itself – and of continuous improvement and innovation to solve various threats in sulfur applications. This paper reviews on detailed description on elemental sulfur, of respective industrial applications, and most importantly highlights on sulfur trends and issues normally encountered.
    Matched MeSH terms: Latex
  17. Chester G, Woollen BH
    Br J Ind Med, 1982 Feb;39(1):23-33.
    PMID: 7066217
    Studies carried out on the occupational exposure to paraquat of plantation workers in Malaysia comprised quantitative estimates of dermal and respiratory exposure of knapsack spray operators, carriers, and rubber tappers operating under their normal working conditions. Spray operators have been shown to be dermally exposed to paraquat by walking through recently sprayed vegetation and into their own spray, regular adjustment and unblocking of spray nozzles and leakage, and overfilling of knapsack spray tanks. Carriers also received measurable dermal exposure from walking through recently sprayed vegetation and accidental spillage when carrying and loading. The infrequent and negligible dermal exposure of tappers resulted from walking through recently sprayed vegetation. Determinations of the total airborne paraquat concentrations in the breathing zone show that spray operators and carriers are exposed to an order of 1% or less of the current TLV for respirable paraquat. No paraquat was detected in the breathing zones of tappers working in simultaneously sprayed blocks. The calculated ranges of dermal and respiratory exposures, when compared with published data on both the exposure to, and the toxicity of, paraquat, indicate that there should be no toxicological risk to any of the three groups studied as a result of using paraquat.
    Matched MeSH terms: Latex
  18. Irnidayanti Y, Soegianto A, Brabo AH, Abdilla FM, Putranto TWC, Payus CM
    Bull Environ Contam Toxicol, 2023 Sep 13;111(3):37.
    PMID: 37704797 DOI: 10.1007/s00128-023-03786-6
    This study examined the characteristics of microplastics (MPs) in the gills and gastrointestinal tract (GIT) of mackerel (Rastrelliger kanagurta) captured in Jakarta Bay, Indonesia. All 120 fish contained MPs, with fragment > fiber > film being the most prevalent types, in that order. The total abundances of fragments, fibers, and films in the gills were as follows: 4.8 ± 1.6, 1.0 ± 0.7, and 0.3 ± 0.3, respectively. The total abundances of fragments, fibers, and films in the GIT were 5.9 ± 2.3, 1.3 ± 0.8, and 0.4 ± 0.4, respectively. Statistical analysis showed that the abundance of fragments, fibers and films in both the gills and GIT of mackerel did not differ significantly between sampling locations. In the gills and GIT, MPs with sizes less than 0.1 mm and MPs that were black in color were most prevalent. Fourier transform infrared (FTIR) spectroscopy tests on MPs from the tissues of mackerel showed that there were 8 different types of MP polymers, namely, latex, nylon, polymethyl methacrylate (PMMA), cellulose acetate (CA), polyurethane (PU), polycarbonate (PC), polystyrene (PS), and polytetrafluoroethylene (PTFE). Latex and polycarbonate were detected in fish samples from Jakarta Bay.
    Matched MeSH terms: Latex
  19. Lam KL, Yang KL, Sunderasan E, Ong MT
    Cell Prolif, 2012 Dec;45(6):577-85.
    PMID: 23046445 DOI: 10.1111/j.1365-2184.2012.00841.x
    OBJECTIVES: Latex from Hevea brasiliensis (natural rubber tree primarily cultivated for its rubber particles) has no known primary metabolic function, although its biological role is as a plant defence system. The present study has evaluated specific anti-proliferative effects of latex whole C-serum and its subfractions, on human cancer cell lines.

    MATERIALS AND METHODS: Cell viability assay using MTT, DNA fragmentation assay and real-time PCR were used to evaluate the cytotoxic effects of latex whole C-serum and its subfractions on the cell lines.

    RESULTS: MTT assay revealed very low LC(50) values, 2.0 and 280 ng/ml, for DCS and DCP treatments, respectively. DCS was proven to be more potent compared to DCP, in conferring specific anti-proliferative effects on the cancer cell lines. The study also indicated that anti-proliferative activity of pre-heated C-serum fractions diminished significantly.

    CONCLUSION: Although noteworthy cell death was reported, DNA fragmentation assay and real-time PCR confirmed that that induced by latex C-serum subfractions was not promoted via the classical apoptotic signalling pathway.

    Matched MeSH terms: Latex/isolation & purification; Latex/pharmacology*; Latex/chemistry
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